Disk separators are centrifuges equipped with a central inlet for the suspension, conical disks which are located in the drum and which act as separators for fine particles as a result of the centrifugal force which is present and the short sedimentation paths. The particles which have been separated out slide along the disks into the solids collection space toward the maximum diameter of the drum. The clarified liquid is discharged over an overflow weir without pressure or under pressure by means of what is known as a gripper designed as a pump impeller.
For low solids contents, disk separators with a closed drum which have to be emptied by hand are in use. For higher solids contents, the drums are equipped with an emptying system which enables the entire contents of the drum comprising solids and liquid to be discharged as a slurry.
Disk separators with a standing or suspended drum are known.
German laid-open specification DE 198 46 535 A1 has disclosed a centrifuge with a suspended drum in which a tubular bag is fitted beneath the drum in order to collect the solid. The vessel in the centrifuge is of cylindrical design in the region of the centrifuging zone of the drum.
This has the drawback that the solids which are centrifuged out can remain stuck in the region of the centrifuging zone, making central collection of the solids impossible.
It is also known that with solid pastes with good flow properties, by achieving an extremely short drum opening time, what are known as partial sludge removal operations are possible, allowing a higher solids concentration to be achieved in the paste which is discharged.
In recent times, it has been attempted to produce a highly concentrated paste by extracting the liquid fraction in the drum before it is emptied and to discharge this highly concentrated paste through a controllable gap which is larger than has hitherto been customary.
For system reasons, the discharge of paste takes place with centrifugal acceleration in the horizontal direction onto a circular periphery, and the paste discharged could be collected in an annular vessel. However, it is desirable for the paste to be collected in a vessel located beneath the drum. This is preferably possible with a suspended drum in one embodiment of a centrifuge. The paste then has to be deflected from the horizontal direction downward into the vessel.